Log audio system used to WebRTC log.

media/audio/cras/audio_manager_cras.cc

Index: media/audio/cras/audio_manager_cras.cc
diff --git a/media/audio/cras/audio_manager_cras.cc b/media/audio/cras/audio_manager_cras.cc
index 6df14bc87191ff8ac16eed8ed3482fca43d53ada..c4bef24ca7831fa65be82a67c51e8a0f131ccd2b 100644
--- a/media/audio/cras/audio_manager_cras.cc
+++ b/media/audio/cras/audio_manager_cras.cc
@@ -228,6 +228,10 @@ AudioParameters AudioManagerCras::GetInputStreamParameters(
   return params;
 }
 
+const char* AudioManagerCras::GetName() {
+  return "CRAS";
+}
+
 AudioOutputStream* AudioManagerCras::MakeLinearOutputStream(
     const AudioParameters& params,
     const LogCallback& log_callback) {